Introduction: Stiffness after primary total knee arthroplasty (TKA) is a severe complication that has been associated with excessive internal rotation of the femoral component.

Methods: Between 2001 and 2004, 18 patients with 18 well-fixed, aseptic primary TKA underwent revision TKA at a single high-volume joint replacement center for stiffness in the presence of femoral component mal-rotation. Stiffness was defined as ROM with less than 90° of maximum flexion or a flexion contracture greater than 10°. Femoral component malrotation was defined as a condylar twist angle of more than 4° of internal rotation using CT scans. Following IRB approval, 17 out of 18 patients (median age at time of the index surgery 62.7 years, range 45 to 78; female, n=11; male, n=6) were available for retrospective outcome assessment. The mean time between primary and revision TKA was 3.2 years (range, 9–79 months). At a mean follow-up of 3.3 years (range, 2 to 6), all patients were evaluated clinically using the Knee Society objective and functional scores, and by CT measurement of femoral component rotation. Patients without additional procedures between primary and index revision TKA (group A, n=9) were compared using Student t-testing with those which had undergone additional interventions (group B, n=8).

Results: Five patients had required additional procedures after the index revision TKA including closed manipulation under anesthesia in one case, patellar resurfacing in one case, metal removal after tubercle osteotomy and open debridement in another case, and tibial component revision followed by revision TKA in one case. CT scans after revision TKA revealed correction of femoral component rotation in all but one case from each group. After revision TKA, the mean objective score was overall 73 points, in group A 82 points compared to 63 points in group B (p< 0.001). In group A there were 78% excellent or good results compared to 13% in group B. The mean function score was overall 74 points, 78 points in group A compared to 69 points in group B. There were 67% good or excellent results in group A compared to 12% in group B. Mean flex-ion increased overall from 71 to 92 degrees (p< 0.01), in group A from 61 to 96 degrees (p< 0.01) and in group B from 82 to 89 degrees. Mean flexion contracture was reduced overall from 7 to 4 degrees, in group A from 6 to 3 degrees, and in group B from 8 to 5 degrees. Stiffness persisted in four cases (24%) (group A, n=1; group B, n=3). Satisfaction (VAS 0–100; 100=completely satis-fied) scored overall a mean of 52 points, in group A 57 points and in group B 44 points.

Conclusion: Overall, revision TKA for knee stiffness associated with femoral component internal malrotation resulted in significantly improved knee motion. However, outcome was less predictable in those patients with additional procedures between primary and revision TKA.

After THR, trochanteric soft tissue abnormalities may be associated with residual trochanteric pain and limping. However, normal MR appearance of the trochanteric region after THR is not known. The aim was to evaluate MR imagings in asymptomatic and symptomatic patients after THR through a transgluteal approach.

Triplanar MR images of 25 asymptomatic (14 men, mean age 60.4 years, 11 women, mean age 60.2) and 49 symptomatic patients (19 men, mean age 62.7 years, 20 women, mean age 64.3) at least 1 year after THR were analyzed by two blinded radiologists. In 14 symptomatic patients MR imaging was correlated to surgical findings.

Tendon defects were uncommon in asymptomatic and significantly more frequent in symptomatic patients (gluteus minimus 8% vs. 56%, p< 0.001; lateral gluteus medius 16% vs 62%, p< 0.001; posterior gluteus medius 0% vs18%, p< 0.025). Signal changes within tendons were very frequent in both groups except for the posterior gluteus medius tendon which demonstrated this finding more frequently in symptomatic patients (20% vs 59%, p=0.002). Changes in tendon diameter were very frequent in both groups but significantly (p=0.001–009) more frequent in symptomatic patients. Fatty atrophy was evident in the anterior two thirds of the gluteus minimus muscle in both asymptomatic and symptomatic patients. In the posterior superior third of the gluteus minimus muscle differences of fatty degeneration were significant. Fatty atrophy of the gluteus medius muscle was only present in symptomatic patients. Bursal fluid collections were more frequent in asymptomatic (32% vs 62%, p=0.021). MR diagnosis was confirmed in all 14 patients undergoing revision surgery.

Although more frequent in symptomatic patients many MR findings are frequently found in asymptomatic patients. However, defects of the abductor tendons and fatty atrophy of the gluteus medius and the posterior part of the gluteus minimus muscle are rare in asymptomatic patients.

The purpose of this study was to analyse a potential correlation of arthrofibrosis (AF) and femoral rotational mal-alignment in total knee arthroplasty (TKA). We hypothesized an increased internal mal-rotation of the femoral component leading to unphysiological kinematic motion of the arthroplastic knee joint. These repetitive microtrauma may then induce increased synovial hyperplasia leading to arthrofibrosis. Arthrofibrosis is an ill-defined entity that results in unsatisfactory outcome following TKA. Biological and mechanical factors have been suggested as etiology, but specific causes have not been identified.

Methods: From a cohort of 3058 mobile bearing TKA 44 (1.4%) cases were diagnosed with arthrofibrosis, of which 38 (86%) cases underwent clinical examination and CT investigation to determine femoral component rotation taking the transepicondylar (TEA) axis as reference point. A control group with 38 well functioning TKA was compared.

Results: Increased internal mal-rotation of the femoral component of 5.0° in the AF group (reference to the TEA) was highly significant (p < 0.001) ranging from 10°IR to 1°ER compared with the control group (0.0° parallel to TEA, 4°IR to 5°ER). Men younger than average for index TKA in this center with a decreased BMI, previous knee surgery (particularly correcting osteoto-mies), poliomyelitis, and OA had an increased risk of developing arthrofibrosis. PCL retaining or sacrificing, patella resurfacing or retaining had no increased prevalence for AF. Rheumatoid patients had a decreased risk of developing arthrofibrosis .

Conclusion: The correlation of AF to femoral component internal mal-rotation was statistically significant (p < 0.001). These results confirm that unphysiological kinematics in TKA appear to be a major etiopathological factor for arthrofibrosis (AF). In this study femoral component internal mal-rotation has shown to be a significant risk factor in the development of arthrofibrosis. We, therefore, recommend consideration of early CT evaluation in cases with AF and, when internally mal-rotated, revision of the femoral component.

This study has been cleared by the Ethical Committee, University of Zurich, Switzerland.

There have been no previous reports of a spinal subdural haematoma occurring as a complication of spinal surgery. We highlight the pitfalls in the diagnosis and management of a subacute subdural haematoma resulting from a dural tear which occurred as a surgical complication of microdiscectomy.